Airport Pharmacy sits in the departure transit area of Changi Airport's Terminal 4, at 10 Airport Boulevard on T4 Departure Drive just after immigration, and holds a 3.8 rating on Google. Airport pharmacies earn their keep with the forgotten and the unexpected: painkillers, plasters, travel-sickness tablets, rehydration salts, insect repellent or a toothbrush grabbed in the hour before boarding. The old travellers' rule still holds — keep medicines in their original packaging in your hand luggage, with a copy of the prescription, because customs at some destinations will ask. If you are unsure what to take on a long flight, ask the pharmacist rather than guessing; they can flag interactions with anything you already take and say honestly when a doctor is the better call. For anyone through immigration at T4 who has realised something's been left at home, it is the obvious stop before boarding.