Ok here's the lowdown:
True ayahuasca is not toxic. If you're brewing a traditional preparation of just chacruna and caapi, you couldn't possibly drink enough to kill you. The only fatal case of "ayahuasca poisoning" was the nicotine poisoning mentioned above. There is also a case of a fatal overdose of pharmahuasca where someone took WAY too much synthetic 5meo dmt with a maoi (I forget which one but it was probably moclobemide or some other synthetic).
Now rue is a different story. Rue is not ayahuasca. However I disagree with those that say caapi is "better" than rue (my plant spirit can beat up your plant spirit, yada yada). You just have to know how to work with rue. One must know the proper way to approach it.
Do NOT eat rue seeds straight up, unless you're a pregnant chick who wants an abortion. Yes there are a number of somewhat toxic alkaloids in rue, such as the uterotonic vasicine, that we normally don't want to ingest for our purposes, especially if we're female.
Brewing a tea is a bit better. The toxic components of rue aren't -as- water soluble as the ones we want. Some say just boiling water and pouring it over ten grams of seeds and steeping for a few minutes, as one would do with a tea, extracts enough of the beneficial alkaloids and not much of the toxic stuff.
Swim sez if you wanna drink a tea, brew with caapi vine. If you wanna use rue, do an extraction. It's actually VERY easy and rewarding to perform alchemy on rue, extracting the gold (harmine and harmaline) from the lead (raw seeds = massa confusia).
I have a tek posted on this. The gist of it is: Simmer seeds in 3% vinegar solution ~45 min (you don't even have to grind 'em up, in fact it's better if you don't). Strain and repeat. Combine liquids. Add 100g UNIODIZED sodium chloride per liter of liquid (morton's canning and pickling salt works great). Put in fridge overnight. Alkaloids fall to bottom of container. Pour off excess liquid and filter to collect alkaloids. Redissolve alkaloids in hot water and filter again to remove excess oils. Then while the solution is hot, add either ace hardware 10% janitorial strength ammonia or else add sodium carbonate, which you can get by baking baking soda (sodium carbonate is swim's preference these daze cuz it smells better). Alkaloids fall to bottom of jar given enough time. Pour off excess liquid, filter, and enjoy. To really clean 'em up, toss 'em in a little boiling water and filter again. They're in freebase form at this point so they won't dissolve, but any impurities will.
And yes any type of huasca experience is vastly rewarding and can change your life drastically. Swim now practices yoga and kung fu regularly, eats all organic healthy foods with no processed garbage, is happier, healthier, looks and feels younger... oh yeah, and he gets laid a lot more often now too. Working with this medicine has been the single most positive change in swim's life. Highly recommended.
Journey well brother!