South African officials say 15 boys have died and 90 have been taken to hospital in the Eastern Cape after botched circumcisions.
The deaths were reported as authorities announced a campaign to prevent badly-performed initiation rites.
Police have arrested six people in connection with the casualties, health official Sizwe Kupelo said.
Mr Kupelo said the authorities were not interfering with the custom of circumcision, but wanted to save lives.
Circumcision is practiced in rural areas of South Africa during winter.
It is a traditional rite of passage for many South African boys. In 2001 the government passed an act requiring a licence from a medical officer for each circumcision, but traditional leaders have said the act infringes community rights.
Most deaths occur after circumcisions in illegal centres.
Health officials linked the recent cases to what they say is parental negligence, the BBC's Mpho Lakaje reports from South Africa.
They say most initiates are sent home after being improperly circumcised, only to die there.
Dehydration has also been cited as one of the reasons for the deaths.