A Nottingham teenager was bitten three times by a taxi driver during a row over fares.
Oliver Tordoff, 18, is recovering from the wounds to his leg and is reluctant to leave his home because he is afraid the driver will attack again.
He caught a private hire taxi outside Nottingham's Queen's Medical Centre (QMC) early on Saturday morning but discovered he had no cash.
The driver then attacked him after he offered to pay his fare later, he said.
Police have taken samples from his wounds for DNA testing, but no-one has been arrested.
Mr Tordoff said he was at the hospital for an ankle injury and flagged down a cab to return home.
He said the row began after he suggested to the driver that he pay later at the taxi office or over the phone by bank card as he had reached his credit limit.
"He stopped the car, dived over the passenger seat, started to be bite me and was ripping my trousers."
Police are reviewing CCTV footage in the area and carrying out forensic tests.
The teenager said he was confined to his home due to injuries but he was afraid the driver might return.
"He stole my house keys and passport and he knows where I live," he told BBC News.
He returned to the QMC for treatment at hospital and was tested for Hepatitis C and Aids.