Bless you modern medicine. If you're home sick with the flu, take comfort in the knowledge you live today.
Before we get started, let me put on an official Doctor-ing costume.
Plague doctor costumes were a terrifying but common sight. The defined bird-nose mask didn't become universal until the 1600s but we're going to run with it.
The traditional costume consisted of a mask stuffed with herbs to ward off bad humors and also to scare away spirits because those bastards were always making people sick. Doctors used the cane to touch infected patients because honestly, who wants to touch plague infested people? Gross.
Source: en.wikipedia.org
If you want to observe without getting sick, hold this.
As medieval theory held sickness was spread by bad smells, pomander balls were a super popular upper class accessory. They held a wide assortment of disgusting ingredients meant to ward off pestilence. The most common mixture included deer musk and ambergris, otherwise known as a by-product of whale poop. Because obviously inhaling fecal matter and deer hormones will keep you healthy.
Source: en.wikipedia.org
Now that we're properly armed, time to consult the urine charts!
Urine charts helped physicians determined an illness based on the quantity, color, smell, and even taste (oh God really??) of the patient's urine. Combined with an astrology table about planet and star alignments, doctors were totally able to 100% accurately diagnosis many diseases.
Source: discoveringmedieval.co.uk
Let's get to diagnosing these poor (rich) people!
Peasants didn't get medical care, except maybe from witches. Doctors ain't running no charity. You've got to pay for this kind of specialized ignorance.
Source: bl.uk