Smith has been a longtime promoter of the medically unrecognized "chronic Lyme disease", and has pushed for the medical establishment to recognize the condition. The condition, not to be confused with genuine Lyme disease, is generally rejected by medical professionals, and its promotion is generally seen as health fraud. In 2019, Smith proposed an investigation into whether the Pentagon had released "weaponized" ticks infected with Lyme disease into the environment between 1950 and 1975. Scientists identified this proposal—which Congress did not adopt—as based on a conspiracy theory and claimed that an investigation was unnecessary and a poor use of funds.