She thought he'd fooled around on her but police say a woman wasn't fooling when she nearly chopped off her boyfriend's penis with a large butcher knife as he slept.

"It wasn't chopped all the way off but it was pretty close," Det. Rich Ryan said moments after the woman's arrest in Scarborough yesterday.

"He also ended up with three lacerations to his testicles."

What began as a domestic spat at a Gilder Dr. highrise Thursday night ended up as a domestic shortening hours later when the 42-year-old victim awoke Friday with a searing pain in his groin and his pyjamas covered with blood, Ryan said.

"It must have been a very sharp pain, for sure," Ryan said.

Ryan said the accused, 36, her hands covered in blood, stood over her wounded boyfriend as he helplessly lay in bed "and said she was going to kill him.

"She ended up trying to choke him instead."

Ryan said the victim's girlfriend refused to call 911, and instead "told him to drive himself to hospital."

Ryan said surgeons were able to reattach the partially severed penis, as well as repair three lacerations to both testicles in a delicate operation. Police said they don't know whether the repaired organ will work at 100% efficiency. Ryan said it appeared the accused, 36, was unhappy because she believed her mate had been seeing another woman. But she was wrong, said Ryan, refusing to elaborate for evidenciary reasons.

The accused, whose name wasn't released by police, is charged with aggravated assault, threatening death and assault with a weapon.

She was later admitted to hospital with undisclosed ailments. Police said the accused's day in court will depend on when she's well enough to go before a judge.

The incident was similar to the sexual severance committed by Lorena Bobbitt, who was charged in 1993 after the penis of her then husband, John Wayne Bobbitt, was lopped off.

A Virginia jury found her innocent of malicious wounding by reason of temporary insanity in 1994.