Get medical advice from your doctor on appropriate jabs well before travelling to India. If sticking to metropolitan areas, just do the basic recommendations. Make sure your rabies shots are current; feral dogs abound in all places in India, especially the cities. If travelling anywhere in the countryside, then by all means get extra jabs for yellow fever, cholera, malaria and anything covering water borne diseases.

It is always recommended to bring with you all the prescribed medications you need for the trip to India, along with the Doctor's prescription as evidence. The prescription itself is essential if you need to top up at local chemists/ pharmacists when in metropolitan areas if your stay in India is prolonged.

It is nearly impossible to get contact lens solution in Kerala.  You cannot get it in chemists, only opticians, and many of the smaller towns do not have opticians.  It would be easier to wear disposable lens or else brings lots of spare solution!

In Chennai, the private medical chain Apollo Health runs many clinics and chemists (pharmacists), some open 24/7. These are highly recommended for any ailments that occur during your stay in India, if you are unfortunate enough to require medical attention. Their chemists operate 24/7, but their stocks vary depending on the affluence and density of the nearby population in the city. It should be relatively easy to get aspirin, paracetemol, Immodium, ibuprofen (locally called brufen), Pepto Bismol, antihistamines, femine products, and other common medical essentials.

In the countryside, medical facilities can be few and far between - and quite basic when they are there. It is best to take your own Emergency kit, including bandages and anticeptic ointment as well as hand wash and Wet Wipes.