It’s not a good idea to drink the tap water, especially in the lowland areas. Street food is usually fine as most of it is cooked on the spot, but steer clear of anything that looks as if it’s been left out for a while. Some people avoid the salad, but it’s not really necessary to be that careful. You’re unlikely to get anything worse than a bit of diarrhea.
Guatemala is a malaria and dengue zone, but to be honest there’s not much you can do about that except wear repellent and hope for the best. You can take malaria tablets, but they have some nasty side-effects, aren’t very reliable, and don’t protect against dengue. The main thing is to see a doctor quickly if you start running a fever.
The name Guatemala is one that’s likely to scare your mother, who’ll be remembering the violence and “no travel” warnings of the civil war period. But these days it’s really pretty safe. Sure, there’s the odd tale of travellers getting stopped and robbed at gunpoint, but that goes for most of Latin America. Most of the world, come to think of it. Just keep your ear to the ground, heed local warnings about dodgy areas, and if possible avoid travelling quiet roads at night.
The most dangerous parts of Guatemala are the cities, especially the capital. It’s not quite as bad as the Lonely Planet would have you believe, but it’s not too far off. Flicking through a local paper, you can’t help but notice that 90% of the articles are about people getting shot. But most of this is due to gang rivalries and doesn’t often affect travellers. Still, walking around Guatemala City after dark is not a risk worth taking. There are plenty of people who are very poor and used to violence, and wouldn’t think twice of putting a knife to your throat for your wallet or camera.
Guatemala is on the coke-trafficking route up through the Americas, and its relative cheapness and availability is an ever-present temptation. The quality is decent, but the pleasure of it is somewhat reduced by the thought of putting your money into a trade which has caused so much misery across the continent. If you do decide to buy, be careful. Coke dealers aren’t the most savoury of people anywhere, and Guatemala is no exception. Watch your back, don’t flash a load of cash or valuables around, and don’t go down any dark alleyways. Just common sense, really. Don’t buy from anyone without a recommendation, as it’s not unheard of for plain-clothes policemen to sell it to foreigners, then have their uniformed colleagues catch up with them two minutes later and demand it back, plus extortionate bribe.
If the police do catch you they’ll make a lot of threatening noises, but keep calm and remember that they’re probably wired to the eyeballs on the stuff as well. Hand it over with a few banknotes and most will leave you alone. Be generous, but not too generous. The size of the bribe will depend on how much they think you have, so put on your best ‘poor’ face and don’t go to a cash point or it’ll be empty before they let you go. And whatever you do, don’t get aggressive or start talking about your rights. Guatemalan jails aren’t renowned for being fun.