I am in a class called "Cleaning Up in Early Modern Europe" about the theory and customs of housecleaning, bathing, laundry, avoidance of disease, etc. in that time period, and I am interested in doing a term paper about hygiene in Western European armies on the march from roughly the 15th to 18th century. Since cleanliness is such a mundane topic, the sort that tends to fall through the cracks of history, I'm a little unsure of where to begin finding both primary and secondary sources. Some of my questions include:

1. How much clothing and linens did they take with them, and what kind of camp followers both male and female? Did they ever stop to do laundry or bathe in streams, or were those luxuries not afforded to the average soldier?
2. With all the prostitution and carousing going on, what did they know about sexually transmitted disease, and what was the impact of epidemics like syphilis on military preparedness?
3. What kind of doctors or surgeons were available, and what sources describe their methods? In the absence of germ theory, how did they try to prevent wounds from getting infected?
4. Where did they all poop, and what kind of sanitation problems did that create?

This is all very vague, so please ask me how I can narrow down the questions to facilitate better answers. I'm kind of trying to find out if there's enough material here to write 15 or 20 pages about, and where to start looking. I'm more interested in the 16th-17th centuries, and I guess if I had to specify a national focus, I'd be interested in either Italy or the Low Countries. Nevertheless, I'm still open to anything. In fact, an alternate idea I had was to look at sanitation or latrines in castles and fortifications.

There is enough material to write 20 pages don't worry.

1. Let's imagine you set up camp next to a river. Would you use the river water to drink, or would you wait until it rains? --> I don't believe you find many sources that include "and on Monday the xx.yy all soldiers cleaned themselves in the river". Why not? Well probably because it is a normal thing to clean yourself.
2. Syphilis was spread by the damn French! That 's all you need to know.
3. For the 15th century I know that they used salvia distillate to clean the wound and close it with a silk thread. And of course the doctor would wash his hands before he'd start the treatment. However in the 16th century hygiene standards fell. For example they no longer washed their hands.
4. Since you are on the march, you just go into the bushes. If you are in camp you dig a hole outside of the camp, put a thick wood above it, so you could sit down and finish.

Hygiene is a very interesting topic. If you are interested get in touch with Andrej Pfeiffer-Perkuhn from "Geschichtsfenster". He is the specialist from Germany when it comes to the late middle ages. If he can't help you, know one can. (Don't worry he speaks English) And he also is very interested of getting the idea of the dirty middle ages out of peoples minds. This is his 15th century display of stuff people had at home to clean themselves. Very interesting!

I have heard that they used chewed twigs as toothbrushes, and that honey was also used to help keep wounds from infection. My wife still uses honey for small cuts, even to this very day. :) ........McM

For a summary of the types of doctoring that could be available, this is a good starting point: https://www.amazon.com/History-Treatment-Prehistory-Nineteenth-Century/dp/0957137702

Thank you for your warm words, Peter.

I will see if i can help.

For the first question: You have to differ between underclothes made from Linen and clothing made of wool. Wool need not very much care as washing etc. In fact it is quite difficult to get good woolen textiles really dirty.
Linen on the other hand get dirty quite easy, but don't smell as easy as modern cotton. But i am sure, that even in field camps shirts and brooches was washed if it was possible.

2nd Question: For the middle age, there wasn't a problem with syphillys, afterwards it seems to be a major Problem, and we know a lot of questionable treatments.

3rd Question: Field Surgeons where quite common and we have books from such surgeons like Hand von Gerdorff (https://en.wikipedia.org/wiki/Hans_von_Gersdorff) which shows a lot of knowledge. They where able to threat even major wounds. On the other hands they had major problems with wounds by bullets, because they transported fibres from the cloth into the wound. So they experimented a lot, with cruel results.

Even without any knowledge about the germ theory, they knew by Experience about the importance of washing the hands. We have a lot of examples that physicians and surgeons washed their hand before examine somebody.

4th Question: In field camps i would except latrines, in normal life poop is a valuable resource which was sometime sold to peasents or Tanners. Real problems are known from huge cities like paris. But most large cities, as an example in the 15th century, have between 10.000 and 20.000 people. Because of this the problem grew over time with the massive growth of the cities.

I hope my answers helped you a little bit. For the 15th century i have a few pictures collected:
https://de.pinterest.com/andrejpfeifferp/hygiene/

Maurice's 'Strategikon', a Byzantine work available in Renaissance Italy, recommends when building a border fortress:

"To prevent the water stored in casks from becoming stagnant and fetid, peg holes should be drilled in them and receptacles placed below, so the water may flow into them drop by drop and kept in motion. When the small receptacles are full, they should be emptied back into the jars or barrels. By this constant movement the water is aerated and does not become foul. It helps to pour some vinegar into water which has started to turn bad, for this quickly lessens or gets rid of the odor."

I don't know if this is the kind of thing you are looking for.

Thank you everybody, I am so grateful for all this information! And yes, Charles, that is the kind of thing I'm looking for.

You'd probably have a much easier time looking for sources after the turn of the 17th century, because that's when we start seeing a huge explosion in the publication of detailed military regulations and manuals. The Raymond J. Lord collection has a couple ( http://www.umass.edu/renaissance/lord/collection.html ) that might give you an idea of what kind of thing to look for although I don't think they specifically deal with camp hygiene (i.e. use them to inform yourself about what military manuals and/or regulations looked like and then take that as a basis in looking for other manuals or regulatons that do have hygiene prescriptions -- I've run across a few but can't access them right now).