Is it ok to take amoxicilin for salmonelia or food poisoning to keep having watery poop?

No it is not unless : It is not a good idea without knowing what is the cause of food poisoning or if it is salmonella proved by culture watery poop can be due to many reasons.The commonest is viral infection, next e coli infection, or shigella most of these infections are self limiting, and all you need is fluids to prevent the dehydration antibiotics should only be taken if prescribed by your physician after culture don.

Salmonella: Salmonella is usually self limited with no antibiotic needed. Antibiotics can potentially prolong the carrier state for the infection. Adequate fluids to prevent dehydration, adequate rest and good nutrition are key. Personal hygiene such as hand washing is essential to protect household contacts. See your doctor for ongoing symptoms.