Enlarge / This 1980 transmission electron microscopic (TEM) image revealed some of the ultrastructural morphology exhibited by three poxvirus, molluscum contagiosum virions. (credit: CDC) The Food and Drug Administration sent a flurry of warning letters this week over bogus homeopathic products falsely claiming to be antiviral cures—products mostly marketed to children. Amazon, Walmart, and the homeopathic company behind Naturasil products were among those receiving warnings for allegedly selling unapproved drugs in violation of federal regulations.