Just because a treatment has been used for a long time or by many people, it does not mean that it helps or that it is safe.
People often believe that treatments that have been used for a long time or by many people must work and must be safe. But sometimes it turns out that those treatments are unsafe or that they don’t help.
For example, in some countries many people have put cow poo on burns for a very long time. They believe that it must help, because it has been used by so many people for so long. However, cow poo is unlikely to help cure a burn. In fact it can make it worse, and make it take longer to get better, if germs from the poo get into the burned skin, causing an infection.