For the Americans reading this question. GST is the Canadian federal tax of 5% over and above the state/provincial tax. There are a few things that are exempt from this federal tax:
http://www.cra-arc.gc.ca/tx/bsnss/tpcs/gst-tps/gnrl/txbl/zrrtd-eng.html
So, at the grocery store, basic groceries (milk, bread, and vegetables) are exempt from this federal tax. That's it.
Should there be a tax on feminine hygiene products? Yes
Also, Jazzy, I love how you probably deny the sexism in your own question. You probably refuse to see the inequality you aspire to. What if the question was reversed? Ignoring feminine hygiene products, shouldn't male-only razor blades, shaving cream and aftershave be tax exempt?