The medicinal use of herbal kelp supplements may cause inadvertent arsenic poisoning and health dangers for consumers, especially when overused, according to UC Davis public health researchers. In a study published in Environmental Health Perspectives, researchers evaluated nine over-the-counter herbal kelp products and found higher than acceptable arsenic levels in eight of them. The study was prompted by the case of a 54-year-old woman who was seen at UC Davis following a two-year history of worsening alopecia (hair loss), fatigue and memory loss during which time she took and increased her dosage of kelp supplements. Symptoms and arsenic levels in her blood disappeared once she quit using the supplements. The study found that none of the kelp products in the study had labels indicating the presence of arsenic, nor were there any warnings about the potential dangers of ingesting large quantities of the supplement.