How do you treat food poisoning?

Fluids, maybe meds. Supportive care, fluids, brat diet (bananas, rice, applesauce, tea), maybe meds. Not always antibiotics; be careful using antidiarrheals-can retain the germ. Probiotics can be helpful. Contact md if prolonged, fever, bleeding, can't keep things down or in.
Food borne illness. There are many causes. Some have illnesses that are self limited like staph and norovirus that are treated symptomatically. Others like salmonella and campylobacter can be treated with antimicrobials if diagnosed early enough. Botulism needs antitoxin and sometimes breathing support.
Variable treatments. Treatment of Food poisoning may include oral or intravenous replacement of fluids/ electrolytes. Antibiotics may be needed for bacterial infections. Hospitalization is sometimes necessary.