Hi there, It is unlikely that it was due to motion sickness, because of the diarrhoea and fever. It is probably a virus, or food poisoning. The most important thing to do right now is to control the vomiting, because he can t keep dehydration at bay if he s vomiting everything back up. Get an anti-vomiting medication like domperidone or metoclopramide from a a local pharmacy, and give it to him immediately after an episode of vomiting to minimise the chances of him throwing it back up. If he can keep it down for at least 30 minutes then it has a chance to work. Don t take anything else in the meantime. Once that is controlled, get him to sip small amounts of plain water or rehydration salts, or if he prefers something familiar, even Gatorade or other non-carbonated isotonic drinks are fine. Give him some paracetamol if the fever is high over 38 C. Don t worry about food until he actually feels like eating. Start plain with bread or crackers, then move on only when he tolerates it well. Avoid dairy and proteins like meat and eggs until he recovers from his diarrhoea. Most episodes of food poisoning or viral gastroenteritis will resolve on its own with no other treatment. Get help if he still can t keep fluids down despite the medication, has persistent stomach pains, if he gets excessively lethargic, or he still has bad diarrhoea after 3-4 days. Ask your hotel for the location of the nearest clinic. Hope this helps, and all the best to you and your family. Regards, Dr. Teh