Cineraria, like other plants in the Asteraceae family, contains toxic pyrrolizidine alkaloids which cause venous occlusive liver disease. However, it is generally recognized that these eyedrops will reverse cataracts in many cases. Recently, I spoke with one of the staff at Schwabe which makes the same type of eyedrop, and they said that regular use of the eyedrops will not cause systemic toxicity. They also said that advanced cataracts take a lot longer to reverse, but they would still work.