The World Health Organization on Friday cautioned people against taking antibiotics if they fall ill from the E. coli outbreak that began in Germany last month.
The U.N. health agency said it supports existing recommendations to avoid antibiotics because it could worsen the condition.
Anti-diarrhea medication also should be avoided because it stops the bacteria from quickly leaving the body, WHO epidemiologist Andrea Ellis told reporters in Geneva.
Some German doctors have recommended that certain patients should be treated with antibiotics.
"If there are particular cases in which that's what the bedside physician has deemed appropriate, then there would probably be good reasons for that," Ellis said.
"But in general we don't want people to pull some antibiotics that they might have sitting around at home," she said. "In addition, anti-diarrheals are generally not recommended."
The outbreak has sickened more than 1,700 people, mostly in Germany, and killed at least 18.
Ellis said it was too early to say whether this particular strain of E. coli is here to stay. Existing rapid testing kits for E. coli don't currently detect the new strain, which until recently had only been found in isolated instances and not large-scale outbreaks, she said.