The E. coli strain that is harmful to humans is E. coli O157:H7, a member of the enterohemorrhagic E. coli group – an intestinally related organism which causes hemorrhaging.
Transmission of E. coli comes from contaminated food, such as ground beef and other cattle products that are undercooked and unpasteurized dairy products. Contaminated foods do not look, smell, nor taste any different than safe products.

E. coli can cause watery diarrhea which can be bloody, as well as vomitng. Abdominal cramps will often accompany the other symptoms.
The Caribou Press and Kelowna Capital News say that there are several homeopathic remedies available for E. coli poisoning:
• Arsenicum album. This is the first remedy to consider when symptoms appear after eating spoiled food. Symptoms start out as simultaneous diarrhea, vomiting and cramping, and the patient will usually desire frequent small sips of water.
• Veratrum album if there are similar symptoms but accompanied with cold perspiration.
• Aloe socotrina. This remedy can be considered when the diarrhea is involuntary and accompanied by mucous and blood. There can be a lot of pain present in abdomen.
• Colchicum autumnale. This is a remedy to consider when the patient is vomiting mucous. The patient can have very dark coloured urine, which could be a sign of the kidneys starting to be affected.
Take all of the above remedies in 30CH potency every 15 minutes until relief is experienced, then every one-hour after that for five or six doses. If no relief is experienced after administering the first four doses, call a homeopath or seek emergency medical help.