It's the size of a credit card, fits easily into a purse, and can protect women against date rape drugs.

Pharmacies across Canada are now starting to stock the Drink Detective, a portable test kit that can check if a drink has been spiked with one of a handful of tasteless "date rape drugs."

The Drink Detective comes with three test strips and a pipette, which is like a tiny eye dropper. The pipette is used to suck a few drops from a drink and then deposit them on three blotters on the card.

One blotter tests for GHB (gamma hydroxybutyrate), a drug popular at rave parties; another tests for ketamine; and the third tests for drugs in the benzodiazapine group, which includes Rohypnol and other anti-anxiety medications such as Valium and Xanax.

The GHB portion of the test shows up as blue if it tests positive, while the ketamine portion turns orange. The benzodiazapine group test is similar to a pregnancy test: two pink stripes mean negative; one pink stripe means positive.

Maciek Zarzycki, a pharmacist in Sainte-Anne-de-Bellevue, Que. says his pharmacy began selling the kits a few weeks ago for $5.99 each. He says the test isn't perfect and false positives are a possibility.

"The quality of each test is very different," he says. "Like, for example, the ketamine test is not very specific for ketamine, but it can also detect ecstasy, speed or cocaine," he told CTV's Canada AM Monday.

"The GHB test is even less specific because it's a pH-based test, the same kind of test we use for swimming pools… So it's not very specific, but at the end of the day, it's still pretty useful because it can always tell you if there's something in your drink."

The plan is to make the Drink Detective available for sale in nightclubs, bars and drug stores. Zarzycki notes that each test can only be used once.

"You can test only one drink with that, and it's not reusable. So it's not really intended to test every single drink you're going to take in a bar. It's more for if you're suspicious about a drink," he said.

Former McGill assistant math professor Stanley Grossman, who's now the managing director of Bloomsbury Innovations Ltd., came up with the test.

He told CTV Montreal that thousands of his tests were handed out in nightclubs in Wales a few years ago, along with a.  poster campaign, warning of the dangers of drink-spiking. As a result, he says, there were no reports of drink tampering and reported sexual assaults dropped by 15.3 per cent.

Grossman says he doesn't really expect that women will begin regularly testing their drinks in darkened, loud nightclubs; he sees the product as more of a deterrent.

"If every woman had a Drink Detective in her purse, and everybody knew that every woman had one, then it becomes much riskier for the bad guy -- or bad girl, as is sometimes the case -- to try to spike someone's drink," he said in a phone interview from London, where he now lives.

Grossman says the best way women can protect themselves is by staying vigilant and never leaving a drink unattended.