A total of 167 people are known to have eaten the infected beef, and six cases of infection with the lethal disease have been confirmed in the Central Asian country's Osh Region. The condition of the other 161 is being monitored.
Vets have decontaminated the site where an infected cow was put down and incinerated.
Eating anthrax-infected meat can result in the gastrointestinal form of anthrax, which has a fatality rate of up to 60%.
Outbreaks of anthrax are relatively common in the Central Asian state. Owners of sick cattle have been known to sell meat from infected animals after culling them, bypassing veterinary checks.
The outbreak is the second in about a month in southern Kyrgyzstan. In early June, seven people were hospitalized with anthrax in the neighboring Jalal-Abad region, of whom one died.
A total of 475 people who have come into contact with infected cattle are undergoing preventive treatment.
Anthrax affects both wild mammals and domestic cattle that ingest or inhale the bacterial spores while grazing. Humans can be affected when exposed to blood or tissues of infected animals.
Anthrax can be highly lethal, but in some forms responds well to antibiotic treatment.