You're probably best off not taking any medication for morning sickness. (don't forget that thalidomide was prescribed as a treatment for morning sickness.) you also want to be careful with any alternative remedies when you are pregnant, your body can react very differently compared to other times. Just make sure you eat well. Some people find changing their diet can help a lot, eating less meat I think is one thing although you have to be sure to get enough nutrition.
Morning sickness is just one of those things that comes with pregnancy, not to everyone, but to some worse than others. The trouble is that these days we are so used to being able to cure the slightest thing that is wrong with us with pills or treatment. I think for most women it stops by about three months.
I have one friend who was sick every day for the whole pregnancy, they said it was very unusual, and wouldn't happen with the next one, but sure enough, sick every day for eight months. She and her husband want a big family, at least four kids, and they are actually quite strict catholics who really didn't believe in birth control, but she said she just can't do it again, so she has had to stop with two kids.