from what i've heard and read about it, vegans do not wear any clothing derived from animals, this includes not only fur and leather, but wool as well (sure the sheep aren't killed but their lives are horribly painful and tortured)
as a vegan, i refuse to buy any animal products, but i do wear a pair of leather sandals that i got long before i went veg. see, vegans are generally environmentally-conscious as well, and don't believe in wastefulness, so it's deemed ok if the product was already purchased, the harm is done, throwing it away won't bring back the animal.
as for medicines. i am a vegan, and i also take meds for a thyroid condition, i cannot live without them. i can live without meat. as far as i know there is no animal fat in my pills, but i am going to do research to find out which brand is against animal testing and switch to it.
more insight into animal testing: i make a conscious effort to buy things that say "not tested on animals" on the label, but sometimes you have no choice. certain products are still illegal to sell without animal testing in Canada, but activists are currently trying to change these outdated and unnecessary laws. as i read in a PETA (People for the Ethical Treatment of Animals) magazine, pouring bleach down a rat's throat does not make it safe for us to drink.
we already know which chemicals are dangerous, there is no need for testing anymore. and research and advancing technology has allowed us to use human corpses for most testing. just not all companies have gotten with the times and switched to that method yet.
everything was tested at some point, so a lot of the companies who don't do testing simply use the research results from previous testing rather than having to do the tests themselves. i don't agree with supporting testing, but i do think that since it was already done, there's no harm in re-using that information, it saves lives of many innocent animals. usually when it's a new company boasting their cruelty-free products, they simply bought test results from other companies, which is great, but some of the older companies reuse their own research, which means they did, and maybe still do (on other products) animal testing, such as the company Procter & Gamble. they are trying to stop using animal testing, and all of their cosmetics are now cruelty free, they just don't boast it because they feel it is misleading because they have previously done animal testing on those products. (i emailed the company this is what they told me in response)
so it's really up to the individual person's opinion on what is right and wrong. no two vegans are alike, they all differ in strictness and opinions.
oh, about the comment about vegetarians being malnutritioned, that's crap. sorry, but it is. how do you think so many vegans and vegetarians live to be just as old, or older, as omnivores? and a vegan diet is much more strict and well balanced than an omnivourous one, most omnivores are more defficient in nutrients than any sensible vegan diet would allow. omnivores generally base their meals around meat, and don't get enough fruits and veggies.
i do take supplements, but not all vegans do, and they make out just fine. i do because sometimes when i work late shifts i can't get all the nutrition i need from food and i need a multivitamin (vegan, no gelatin or other animal products in my vitamins

) actually i don't even take my vitamins every day, like when i'm home all day i know i can eat properly and i don't take them, but if i'm working i take one because the food at work is not particularly healthy. i'm usually limited to salad and cheeseless pizza, which is ok for a vegan meal, but it's missing the protein i need.