I've been experimenting with Alchemy in Skyrim, and I've noticed that I've acquired two distinct alchemical effects: "Damage Health" and "Ravage Health". They both cause instant poison damage, so what's the difference? Why do some ingredients give "Damage Health" while others give "Ravage Health instead?"
I just tested it myself by combining a harmful effect with a good effect, allowing me to drink the poison. Ravage does not decrease maximum, but rather is a very, very strong DoT effect that lasts 10 seconds. I took something that ravaged magicka by 12 points, and I soon lost half my total mana as the timer counted down - I had 194 total mana. This effect wore off after 10 seconds and the good effects of the potion continued working. My maximum did not seem affected.