In my opinion, when you find a certain therapy being criticized as being unproven quackery, then that is a pretty good sign that the alternative therapy is effective and safe. Big pharma would not waste their time preparing reports designed to warn people against using an alternative therapy unless that therapy is effective and has the potential for being a threat to their monopoly.
​Comfrey's use dates back centuries to at least the time of the ancient Greeks. During the Middle Ages comfrey was a widely cultivated herb found extensively in the gardens of monasteries. Throughout the 1700's and 1800's comfrey was also a popular herb grown in many gardens across Europe as well as America. Sometime during the late 1970's however research revealed that comfrey when taken internally can cause severe liver damage so it has lost popularity and internal use is even banned in many countries. Applications in the from of ointments, poultices, or creams are still considered safe though. Comfrey can still be found growing wild in central Europe, and the eastern United States as well as  a few western states.
Eating a clove or two of fresh garlic a day may indeed keep the doctor away, in part because it has immune-boosting, antibacterial, antiviral, and anti-fungal effects. Many of garlic's therapeutic effects are derived from its sulfur-containing compounds, such as allicin, which are also what give it its characteristic smell. In general, garlic's benefits fall into four main categories: