Q: A co-worker has a history of breast cancer. At her recent checkup, her white blood cell count was low. She began adding liquid chlorophyll to her water, saying it increases oxygen in the blood, cleanses the liver, deodorizes the bowels, and removes toxins from blood tissues, bones and the intestines. I have searched for information on this, but have only found anecdotal evidence. I found one statement that said that too much chlorophyll was poisonous. Is there any evidence that chlorophyll does these things?

A: No. There is no good evidence at this time to support the claims that chlorophyll does any of the things you mention.

Chlorophyll is the green matter in plants. It is chemically similar to heme, which is a chemical in human red blood cells. In chlorophyll, however, there is a central magnesium atom. In blood, this central atom is iron.

There are some very early, basic studies that suggest the similarity between the two chemicals might enable chlorophyll to protect people from some of the potentially harmful effects of red meat, which contains heme.

These studies suggest that the heme in red meat might be changed in the gut into other chemicals that could be harmful, and that perhaps green vegetables that contain chlorophyll could protect against these harmful chemicals.

This might be why some studies suggest that eating a diet rich in green vegetables can reduce the risk of colon cancer. But the connection between chlorophyll and reducing cancer risk has not been proven.

I do not believe there is any good evidence to support the other claims you mention. More studies of chlorophyll are clearly needed.