Not all herbs or beneficial an example would be poisonous mushroom, nightshade plants, and poison ivy.
Don't fall for the idea that if it's natural and it's an herb that is good for you.
Here's a list of several herbs that are toxic to the liver, peripheral blood mononuclear cells (PBMC) from normal controls identified and separated from other cells of the blood by centrifugation and toxic in the cytokine p450 assay.
List of herbs and supplements I do not recommend except for short periods of time and if they have other beneficial value in a specific area that someone needs support in
Angelica, Bayberry, Bilberry, Birch, Blue cohosh, Boneset, Bachu, Colloidal Minerals, Colloidal Silver, Coltsfoot, Comfrey, Feverfew, Fo-ti, Gotu-Kola, Horseradish, Juniper, Kava Kava, Licorice, Longspur, Mistletoe, Mullen, Nettle, Poakweed, Seneca, Una de gata (Cat's Claw)
JANA 1999 Vol.2, No. 1