Yes. In the 1950s perchlorate was approved by the U.S. Food and Drug Administration as a safe and effective medication to treat people with overactive thyroid glands. While it has been replaced in the U.S. with newer medications (partly because enormous doses were required to have any effect and had to be given frequently as perchlorate is rapidly eliminated from the body), [1] perchlorate is still used as a medicine in other parts of the world. Becaue of its long-standing use as a medicine, we know much more today about how perchlorate works in the body.

 [1] In the early 1960s there was a concern that perchlorate might have an association with aplastic anemia. Seven patients who were being treated with perchlorate developed the disease. There were several possible reasons why, ranging from misdiagnosis of hypothyroidism to environmental concerns (the cases were clustered in two specific areas). No evidence of a connection between perchlorate and aplastic anemia has been shown. What is known is that in the four decades since, perchlorate has continued to be used and no cases of aplastic anemia have arisen among any of these patients.