Greater celandine, like other members of the Papaveraceae (poppy) family, contains alkaloids as its major constituents. These include chelidoxanthine, chelidonine, and coptisine. Greater celandine extracts have been shown to stimulate production of bile and pancreatic digestive enzymes in human studies.⁵

Animal and test tube studies have shown that the alkaloids and whole plant extract can relieve gallbladder spasms and stimulate an under-active gallbladder.^{6, 7} Test tube and animal studies have also shown celandine extracts and purified alkaloids to have anti-inflammatory, anti-cancer and antimicrobial properties.^{8, 9, 10} They have also shown greater celandine’s ability to protect animal livers from toxic substances.^{11, 12}

A double-blind trial found that a standardized extract of greater celandine could relieve symptoms of indigestion (such as abdominal cramping, sensation of fullness, and nausea) significantly better than a placebo.¹³ The trial used an extract standardized to 4 mg of chelidonine per capsule and gave 1–2 tablets three times daily for six weeks. An earlier, preliminary trial also found the same extract reduced symptoms in people with indigestion.¹⁴

Preliminary reports from Russia and China have reported that a tincture of greater celandine applied topically was useful for warts.¹⁵ However, these results have not yet been confirmed by double-blind clinical trials.

Several reports describe Eastern European clinical trials using semi-synthetic derivatives of greater celandine alkaloids for people with cancer.¹⁶ This injectable product goes by the name Ukrain®. The findings on this drug cannot be applied to greater celandine because the alkaloids have been modified from their original form.