All healthy people are alike, but all sick people are sick in their own way. You can not find equally sick people. Treated by different combinations of drugs two similar patients, i.e. patients with similar sicknesses, are moving on diverging roads. This is due to their inability to realize that the drugs they take interact not only with them but also with each other. If you take a lot of different medications, you might get cured of something, but you will definitely get something else.
How many drugs are on the market? There are different answers on the net, averaging around 12000. Sounds reasonable, as there are about 12000 diseases in ICD-9 (International Classification of Diseases of the World Health Organization)*. Combinatorics says that the number of different interactions between 12,000 drugs is 2^12000 (a number with 3613 digits, which is greater than the number of atoms in the visible universe). If you believe that there exists some supernatural being able to study all these drug interactions (and find that all of them are health-improving), then you definitely need medication.
Now we know why every sick person is sick in their own way (they use different combinations of drugs to reach unique complaints). And why are the healthy people alike? Because they do not take any medications.
* this is a translation of an old text of mine, now we have ICD-11