Well, medicines is something foreign that get's injected into the body. Scientist battle a constant battle against the body's own immune system since the immune system don't like most medicines (you have to disguise them or temporarily paralyze the immune system) why shouldn't a wizards magic react the same? I would say that the magic neutralizes the foreign substances since it beliefs that it may be hazardous.

Also, a cold is not really the same thing as a full on disease. I think that diseases is more of the plague sort. Or something like that. STD's too...

 

We should note, however, that the only time we hear about this is during the exam period. Exams are stressful.

We hear in HBP about how Tonks is depressed affects her powers (she can't use her metamorphmagus powers).

I would suggest that the students got colds because the stress of the exams negatively affecting their powers.

 

HP Lexicon disagrees with you.

 

I stand corrected.

Though I think it is mentioned in one of the books about many students getting colds during an exam period. Or something.

 

Amazingly enough it's just like a disease. It's caused by a virus like, STD's. It's just that in modern times we have tons of symptom killers (antihistamines, decongestants, anti-viral meds, and the like) that make the experience commonplace. Depending on a person's general health the common cold can lead to pneumonia and a painful death if not treated properly.

I understand what you are saying though. Blood draining from one's eyes, or a virus that makes your dick look like your foot wrapped in coral is much more severe.

 

Just for the record, STDs are called STIs now.

Let's keep this in the now.

 

Pfft. Next you'll tell us Pluto isn't a planet.

 

Useful plot device.

 

Just to touch the Pluto thing again...
The Kuiper Belt, is full of what are now considered KBO (Kupier Belt Objects) like Pluto. And seeing as how some of these KBO things are bigger than Pluto and yet not considered part of the planets in our solar system, Pluto lost it's title as the last planet.

I know I know, not on topic....

On Topic!!
I think Wizards are affected by modern muggle medicine. I don't really see a reason as to why they wouldn't be.

Saint Mungo's Hospital for Magical Maladies and Injuries.
Well even if it is only for "Magical" Maladies, wizards wouldn't know the difference between a muggle illness or a wizard illness when there is one. Their lack (and fear) of muggle science probably leaves them to believe that even the common cold is a result of magical illness so we can't really make the assumption that they know the difference between the two.

 

And Backwards Compatible. Good luck with getting updates from the phantom author.

Probably better luck with Culture Shock, considering their relative ages.