What happened in Bangkok in late September 2026

According to news reports, between 24 and 27 September 2026 Bangkok received continuous heavy rain of about 300 mm in roughly 48 hours, flooding streets and ground floors across the city. On 26 September 2026 the Bangkok Metropolitan Administration declared all 50 districts a disaster zone. Eastern Bangkok was hit hardest, with Khlong Chan and Bueng Kum among the areas mentioned. Governor Chadchart said the canals were full and that drainage would take two to three days after the rain stopped.

Lives were lost during the event, and we extend our sympathies to every affected family. As of 30 September, some roads, including Si Burapha and Lat Phrao, still had 20 to 40 cm of standing water. Thai media compared the event with the 2011 floods, and one Thai business report cited a Chamber of Commerce estimate of about 12,300 million baht in damage.

Among the many businesses affected, pharmacies and medical supply shops carry a special responsibility. Most of their customers are already unwell, elderly, caring for a bedridden relative, or buying medicine for a small child. After the water recedes, these are often the first shops a community needs open again. They are also the shops that should least follow a "wipe it down and start selling" approach.

A typical scenario: a corner pharmacy in Khlong Chan the morning the water dropped

(This is a typical scenario compiled from common post-flood situations. It is not a statement from a real person.)

Fon, a pharmacist, has run a single-unit shophouse pharmacy at the mouth of a soi in the Khlong Chan area for almost ten years. Her regulars include an elderly woman who buys blood pressure medicine every month, young mothers who come in for oral rehydration salts and fever reducers, and adult children who buy or rent wheelchairs, walkers and underpads for bedridden parents at home.

On the night of 25 September, water from the road rose to the shopfront and flowed under the roller shutter, flooding the shop floor to about mid-shin. Fon and her husband lifted medicine from the bottom shelves as high as they could, but cartons of adult diapers, bags of underpads, cases of wound-cleaning saline and the walkers displayed at the front stayed underwater for hours. The power was cut, and the refrigerator for temperature-sensitive medicines went silent all night.

On the morning of 28 September, when the water had dropped enough to open the shutter, she found a thin film of mud over the tiles, rust starting on the steel shelf legs, a swollen plywood partition behind the counter, cardboard boxes in the stockroom gone soft, and a damp, drain-like smell hanging in the air. Before she had even opened, regulars were knocking on the shutter asking for their usual medicines, because the bigger pharmacy in the nearby mall was still closed.

As a pharmacist, Fon knew she had to discard every medicine that had touched floodwater and handle her refrigerated stock with care. What worried her just as much was the shop itself: the shelves, the counter, the stockroom and the air that dozens of vulnerable customers would breathe each day while waiting for their prescriptions. She did not want a place people rely on for their health to become a place where sick people pick up more mold or bacteria.

Why pharmacies and medical supply shops face higher germ risks after a flood

1. Your customers are vulnerable by definition

People who walk into a pharmacy are often ill, managing a chronic condition or caring for a patient. Older adults, people with diabetes, lung or kidney disease, cancer patients in treatment, pregnant women and young children are all more likely to be affected by environmental mold and bacteria than the general public. A pharmacy should therefore be exceptionally clean, not just "clean enough".

2. Floodwater brings in sewage and rodent-borne germs

Water that enters a roadside shophouse is a blend of rain, drain runoff, canal water and sewage. It can carry faecal bacteria such as E. coli and the leptospira bacteria spread through rat urine, which cause leptospirosis. These settle on floors, shelf legs, wall crevices and product boxes. Shophouses where rats live in pipes and ceilings need extra care, because rats tend to flee rising water into buildings.

3. Shops are full of paper, cardboard and absorbent goods

A pharmacy stockroom holds cartons, medicine boxes, labels, invoices and absorbent products such as underpads, adult diapers, cotton wool and gauze. All of these soak up water and feed mold. With lingering moisture, mold can begin growing within roughly 24 to 48 hours, according to general CDC and WHO guidance. Spores from a moldy box can drift onto stock that never touched the water in the same room.

4. Medical equipment has complex surfaces

Wheelchairs, walkers, canes, adjustable patient beds, air mattresses, blood pressure monitors and nebulisers combine fabric pads, rubber tyres, hinges, tubes and many joints. Mud and water can lodge in places you cannot see. If a shop returns flooded display equipment to sale or rental without thorough cleaning, contamination can travel straight into a patient's home.

5. Small, poorly ventilated spaces with constant foot traffic

Most shophouse pharmacies are long, narrow rooms with a single front entrance and one or two split-type air conditioners. Closed for days during the flood, humidity builds in both the sales floor and the back stockroom. Once the shop reopens, customers who are coughing, sneezing or feverish stand in the same tight space as older people and children.

Symptoms to watch

Damp air and mold spores can cause a blocked nose, sneezing, coughing, eye and skin irritation, and may trigger asthma or allergies. Contact with sewage-contaminated surfaces may be linked to diarrhoea, stomach pain and wound infections. Shop owners, staff and customers who waded through water should all watch their health closely.

Important: Anyone with fever, muscle pain (especially in the calves), red eyes, diarrhoea or an inflamed wound after wading through floodwater should see a doctor promptly and mention the exposure. A pharmacist can give initial advice and refer customers to hospital, but ozone treatment is not medical treatment.

What happens if a shop reopens before recovery is complete

Customer and staff health

Patients waiting for medicine may breathe air carrying spores and a musty smell. Staff who stand behind the counter all day are exposed for hours at a time. If the plywood partition or ceiling behind the counter is still damp, mold can keep growing where nobody looks.

Money and stock

Flooded stock has to be discarded anyway. If the stockroom still harbours mold, however, new deliveries end up stored in a damp, spore-laden room, which damages boxes, stains labels and may force another round of disposal. For a small shop with limited cash flow, that is a double loss.

Time and service to the community

The days after the water drops are when neighbours most need basic medicines, rehydration salts, wound care and patient supplies. A shop forced to close again because the musty smell returns or new mold appears loses both income and the chance to help the people around it.

Credibility

Customers expect a pharmacy to be cleaner than an ordinary shop. A musty smell at the door or mold on the walls can instantly shake confidence in the medicines and in the pharmacist's advice, even when every product on the shelf is new and never touched the water.

Patients' families

Medical supply shops that rent wheelchairs and beds deliver directly to the homes of bedridden patients. If equipment or storage is not clean enough, the risk does not end at the shopfront. It travels into the bedroom of the most fragile person in the family.

Why a rushed wipe-down is not enough for a pharmacy

Wiping shelves with alcohol or bleach only: This disinfects smooth surfaces that have already been washed, but does not reach behind shelving, under the counter, into plywood grooves or into the stockroom air. Chlorine fumes in a small shop can also irritate customers with respiratory conditions.

Leaving the shutter open with fans running: This helps ventilation, but while the road outside still has standing water and mud, an open shutter can bring dried mud dust and street humidity straight back in.

Air freshener or charcoal deodorisers: These reduce the smell you notice, not the microbes causing it. Fragrance in a pharmacy may also make some customers dizzy or trigger allergies.

Painting or wallpapering over water marks: If the inside of the wall is still damp, paint and wallpaper trap moisture and mold. Stains soon return, often worse than before.

Restocking the old shelves immediately: If shelving and the stockroom have not been washed, dried and disinfected, new products go straight into the same risky environment.

All of these share the same gap: none can treat the whole room, including surfaces, hidden corners and the air, in one go. That is where ozone treatment adds value, once the shop has been washed and dried.

WHD ozone disinfection for pharmacies and medical supply shops

According to World Health Disinfection (WHD), ozone (O3) is a fast-reacting gas. Released into a closed room at a concentration set by the technician, it spreads through the sales floor, stockroom, behind the counter and between shelving units. Ozone breaks down the cell structures of viruses, bacteria and mold and breaks apart musty odour molecules, then reverts to oxygen (O2) without leaving chemical residue. According to the test results certified for the company by Thailand's Department of Medical Sciences and Intertek (UK), it eliminates viruses, bacteria and mold at 99.99%.

How the work runs in a shop

1. Survey the shopfront and stockroom: The team assesses floor area, ceiling height, air conditioner positions and how far the water reached, then divides the shop into zones such as the sales floor, stockroom and staff toilet.
2. Confirm the shop is washed and dry: Flood-exposed stock has been removed, mud washed out, shelves and counter cleaned, swollen materials stripped out and the room reasonably dry. Ozone comes after cleaning. It is not a substitute.
3. Manage stock and equipment first: The pharmacist and the team agree on moving medicines, opened products, temperature-controlled items and sensitive electronics out of the treatment zone, following the technician's advice.
4. Empty and seal the room: No people, pets or plants in the zone. The shutter is closed, air conditioning is temporarily switched off and a sign tells customers the shop is closed during treatment.
5. Release ozone and hold contact time: The generator runs according to room size, with a typical cycle of about 30 minutes per zone.
6. Rest and ventilate: The room rests until the ozone reverts to oxygen, then it is ventilated. Staff re-enter at the time the technician specifies, and only then is stock returned to the shelves.

For ozone jobs of 15,000 baht or more, WHD currently includes a free medical-grade disinfectant spray, useful for daily wipe-downs of counters, change trays and other high-touch points.

For disinfecting surfaces and equipment after the mud is washed off, see the Chemgene HLD4H medical-grade disinfectant. If repainting or new shelving leaves chemical odours, WHD's ozone chemical-residue and odour removal service is a separate option.

10 reasons pharmacies and medical supply shops should consider ozone before reopening

1. Your customers are a high-risk group, so reducing microbes in the shop protects patients from the moment they step through the door.
2. It reaches behind shelving and under the counter, where cloths cannot go and where moisture collects after a flood.
3. It treats stockroom air, reducing spores that may drift from damaged boxes onto other stock. See the residential and building ozone disinfection service.
4. It leaves no smell or chemical residue, because ozone reverts to oxygen, which suits customers who are sensitive to odours.
5. It tackles musty and drain smells at the source, restoring the clean atmosphere a health shop should have.
6. It is quick. A typical cycle of about 30 minutes per zone means it can be done after closing or before opening.
7. It is backed by test results certified for the company by the Department of Medical Sciences and Intertek (UK).
8. It suits medical equipment showrooms full of wheelchairs, walkers and beds, once the equipment itself has been washed and wiped.
9. It helps protect new stock, so deliveries after the flood are not stored in a room still carrying mold and damp.
10. It builds community confidence, letting you tell customers the shop was washed, dried and disinfected. Details are on the ozone disinfection service page.

Before and after: the difference customers feel

Example case: a medical supply shop on Si Burapha Road

(An illustrative example to explain the process, not a verified customer review.)

Oat runs a medical supply sales and rental shop in a two-unit shophouse near Si Burapha Road. The ground floor is a showroom for wheelchairs, patient beds, air mattresses and blood pressure monitors, and the back room stores adult diapers and underpads. During the flood, the road outside stayed waterlogged for days, and water seeped in until the whole ground floor was wet.

His first step after the water dropped was to photograph the damage for his records. He then removed every product that had touched floodwater: diaper cartons, underpad bags and the foam mattresses on display. For metal-framed wheelchairs and walkers, staff removed the pads, washed the frames with clean water and detergent, scrubbed joints and wheels, then wiped them with disinfectant. Soaked fabric pads were replaced. Every electrical device that got wet was set aside for a technician and kept off sale and out of rental until checked.

After stripping out the swollen plywood wall lining and running two dehumidifiers for two days, Oat booked WHD to treat the showroom and storeroom on the same night. Following the technician's advice, he moved the remaining electronics upstairs outside the treatment zone, closed the shutter, kept everyone out during treatment and waited for the full rest period before going back in.

The next morning, he noticed that the musty smell trapped in the storeroom had largely gone, and he felt comfortable ordering a new batch of diapers into the same room. He added a disinfectant wipe-down for every item before it goes out on rental, and posted a notice at the front explaining that the shop had been cleaned and disinfected after the flood. A customer renting a bed for her mother, newly discharged from hospital, said seeing those steps put her mind at ease.

Recovery checklist for pharmacies and medical supply shops

Before ozone treatment

• Photograph the damage and list affected stock for insurance or assistance claims.
• Have an electrician check wiring, sockets and the medicine refrigerator before switching on.
• Remove every medicine and product that touched floodwater. Do not resell it, even if the outer packaging looks fine, and dispose of it appropriately.
• Review refrigerated medicines that may have lost power, following manufacturer information or professional guidance.
• Wear rubber gloves, boots and a mask while washing the shop.
• Remove mud and wash floors, shelf legs, counters and lower walls with clean water and detergent.
• Strip out swollen materials such as plywood, gypsum board and stockroom cartons.
• Remove and wash or replace fabric parts on medical equipment, and set aside wet electrical devices for inspection.
• Have the air conditioner coils and drain pans cleaned.
• Dry the shop with ventilation or dehumidifiers.
• Move medicines, opened products and electronics out of the treatment zone as advised, and remove any plants or pets.

During and after ozone treatment

• Close the shop. No people, pets or plants in the treatment zone, and post a notice for customers.
• Wait for the full rest period, then ventilate before entering.
• Return stock only to clean, dry shelves.
• Disinfect counters, change trays and high-touch points daily.
• Disinfect every rental item before handover.
• Control stockroom humidity and check corners for new mold over the following week.

Frequently asked questions

1. After ozone, can flooded medicines go back on sale?

No. Medicines and products that touched floodwater should be discarded. Ozone treatment disinfects a shop that has already been washed and dried. It does not rescue contaminated stock.

2. Must all medicines leave the shop before treatment?

The team will assess with the pharmacist or owner which items should leave the treatment zone, especially opened products, temperature-controlled medicines and electronics. Agree on this clearly before work begins.

3. How long must the shop close?

A typical cycle is about 30 minutes per zone, plus the rest and ventilation time the technician specifies. Most shops schedule treatment after closing at night or early before opening.

4. What about display medical equipment?

Equipment should always be washed and wiped first. For electronics or parts with special manufacturer conditions, tell the team in advance so they can be moved out of the zone.

5. Is it worth it for a small single-unit shop?

When your customers are patients and older people standing close together in a narrow space, reducing microbes is an investment in safety and credibility. The team can assess the actual space and quote accordingly.

6. A staff member has a fever after helping clean. What now?

They should see a doctor promptly and mention floodwater exposure, especially with muscle pain or red eyes, which may be linked to leptospirosis. Ozone treatment is not medical treatment.

Let the shop that cares for your community be clean and safe first

Talk to the WHD team about ozone disinfection for pharmacies, medical supply shops and stockrooms after the Bangkok floods 2026.

Get Advice on Ozone Disinfection for Your Shop

Call 065-556-6294 · LINE @whd268 · Email worldhealthdisinfection@gmail.com

Related services

• Residential and building ozone disinfection
• Chemgene HLD4H medical-grade disinfectant
• Ozone chemical-residue and odour removal

References

• 2026 Bangkok floods – Wikipedia
• Al Jazeera: Disaster zone declared across Bangkok
• CDC – Floods and cleanup
• WHO – Fact sheets