If I remember correctly, smoking or being around someone that is smoking all the time can raise it. Also steroid drugs and probably a few other drugs as well. Try Milk Thistle guaranteed potency, the stronger active ingredient of silymarin in it. I believe I had my sister take 200 mg with 175 mg of silymarin in it, once or twice a day. She used to smoke and was put on steroids for a skin condition and her ALT would shoot up and they would have to stop the drugs until they finally dropped. Milk Thistle dropped it really nicely, but of course then she just ended up back on steroids faster so not sure how good that was for her.
Phyllis Balch’s Book Prescription for Nutritional Healing and Louise Tenney’s Book Today’s Herbal Health both well respected authors in the natural world talk about it, but I’m sure you can punch in Milk Thistle and the liver into google search and all sorts of information will come up. Milk Thistle was the first most researched herb because of it’s help with the liver.