Diarrhea and stomach troubles are the main problem. Indians have no trouble believing in gods with blue skin but invisible bacteria still strike most of them as wild fantasy. I remember asking a waiter to take his fingers out of my tea. He looked at his hand and protested that it wasn’t dirty.
The main thing is only to eat food that’s been freshly cooked. The longer it hangs around(especially rice) the riskier it is. Choose places that look busy so there’s a fast turnover of food in the kitchen. Avoid touristy places as they may reuse food that’s been kicking around for weeks.
Also don’t eat street food unless you’re feeling lucky. Train food is often the worst of all. Take your own food with you when you travel. Bananas, nuts and some biscuits.
Always wash your fruit carefully and peel it if you want to be on the safe side.
Eating yogurt and rice together is the best cure for diarrhea.
Eating some raw garlic will take care of many stomach worms.
For many travellers in India drugs are simply part of the experience. Educate yourself first though and make sure you never take more than is right for you. Everyone has their own limits and they must be respected.
Charas, the hand-made hashish, is the most popular sacrament. There’s also opium but you need to be more careful with this. Ketamin has become popular in recent years but you have only to look at someone on it to see what a sleazy, dirty drug it is. Good quality LSD is around in the party scene in Goa but don’t take this lightly. Stay away from datura. Check out the Road Junky drug guide.
Drugs can get you serious jail time too, like ten years if they decide you’re dealing. The police in India are as bad as the thieves. Corrupt through and through they’re paid so little that they have to try and make a living by extorting baksheesh wherever they can. If they catch you with drugs or without a visa then you can expect to pay your way out of the situation. Be polite but aloof and do what you can to take control of things. Play it by ear but if you’re too submissive they’ll take all you have on you at the time.
For more on staying safe check out the Travel Health Guide