Toronto police are asking for the public's help in finding a woman who allegedly stabbed another woman for no apparent reason inside a pharmacy at Bay and Wellington Streets Friday.

The alleged perpetrator brought a knife into the store and then stabbed another woman "without provocation" on Friday around 2:55 p.m., police said in a media release Saturday.

The incident happened inside the Shoppers Drug Mart in the underground PATH system in the TD Centre, police say.

The victim was taken to a trauma centre with life-threatening injuries. Investigators are treating the incident as an attempted murder.

Police released a photo of the alleged assailant, which shows a white, dark-haired woman wearing a dark blazer and matching skirt. She's also wearing a lavender collared shirt and appears to be carrying a red shopping bag and a black overcoat.

Police are asking that anyone with information about the incident to contact them at 416-808-5204 or Crime Stoppers at 1-800-222-8477.