my mom always made a warm tea with honey

cistus incanus tea

NAC

ganoderma lucidum

mms

serrapeptase

vitamin D, 50,000 IU for 2 days

Vitamin C, non-GMO, up to bowel tolerance

Propolis

But it all comes down to finding out the category of the cause (virus/bacteria/fungi/parasite) and target more directly that category.