There is no point engaging with someone who cannot understand either the problem with anecdotal data or the purpose of double-blind studies. Most viral diseases have a high recovery rate when people get medical attention, bed rest, and hear that they are receiving useful pharmaceuticals. If you have a healthcare provider tell someone that jelly beans and vodka will speed recovery, they will recover more rapidly than they would without any medication, and ascribe their survival to these miracle drugs. Literally thousands of studies have demonstrated this psychological effect.
When I was a pre-med student, I read a study that found sugar pills were nearly as effective as acetaminophen in treating mild headaches. One factor was the power of belief in reducing muscle tension, another was that most people drink more water when they take pills... and water is a fairly effective treatment for many headaches. A lot of people underproduce vasopressin, a hormone that tells you you're thirsty, and so become dehydrated without sensing it. Dehydration causes headaches.
Hope this helps.