Contrary to the common depiction, the 'germ theory', although invaluable to the subsequent development of medicine and related fields of knowledge, was not necessarily a paradigm shift. 'Germ theory' was essentially a series of observation and experiments that allowed the scholars to identify the pathogens and their role in the process of infections and transmission of the diseases what allowed them to develop much more accurate and efficient ways of curing and preventing infectious diseases. But long before these scientific breakthroughs, people generally had an instinctive understanding of the link between dirt and infections as well as of the various infection vectors, even though they were not explain them adequately. They might have not known about the existence, let alone the influence of the bacteria or viruses, but they knew that one should not keep open wounds dirty, exposed or bleeding and they knew that it is generally a good idea to share a room or even approach a person suffering from some of the conditions known to be contagious, such as leprosy or pestilence.

The idea that a wound needs to be cleaned and protected from contamination is millennia-old, very possibly reaching back to prehistory. One of the earliest written mentions of wound washing and binding them in appropriate dressing come from around 23rd century BCE. Thai is generally thought to be a result of observation, as the dirty wounds tended to heal more slowly and the patient were displaying signs of inflammation or other pathological states (e.g. fever) more commonly. The association between filth, dirty objects and lack of health was also quite prevalent, so the necessity to keep the wounds clean is seen as natural requirement in most preserved medical texts.

In the areas where wine, and by extension, also vinegar became popular, these two products became a widespread wound cleansing agents, as evidenced by writings of e.g. Hippocrates of Kos. Mediterranean people also tended to use various mineral copper compounds that were easily available due to the ubiquity of the copper. Majno posits that Egyptians might have started to do it as the greenish mineral preparations were used for practical and spiritual purposes, as Ancient Egyptians tended to associate green colour with health and life, with the application of copper compounds being later adopted by e.g. Greeks. The compounds used in Egypt were most likely malachite (copper carbonate hydroxide) and chrysocolla (copper phyllosilicate hydroxide) while Greeks tended to use verdigris (copper carbonate, chloride or acetate).

Albus Cornelius Celsus (c. 53 BCE-7CE) in his book De Medicina differentiated between chronic sores and fresh wounds, indicating that the latter should be quickly cleaned and sutured to facilitate healing. The works by Celsus, Galen and Pliny the Elder (primarily the Historia Naturalis) present a substantial number of the wound dressing that are not different from what has been commonly used around that time in the Mediterranean area for centuries, with wine and vinegar, cobwebs, astringents like ink used to write on papyrus (usually containing substantial content of tannin and gallic acid) and absorbent clay being the most common ingredients. It is generally accepted that ancient and by extension also early medieval doctors understood that various substances can have various effect on the wounds and differentiated between styptics (hemostatic agents, used to reduce bleeding), astringents (used to contract mucous membranes and exposed tissues) and antiseptics, although in the case of the latter they were simply used to keep the wound clean, as nothing suggests that aforementioned scholars possessed any understanding of the microbial action or presence.

Greek and Roman medical texts that heavily influenced Middle Eastern and medieval European medical practices also contained procedures used in case of more dangerous wounds associated with the damage to the blood vessels. In such cases simple surgical procedures were used, such as usage of styptics or even pressure in case of small cuts or the isolation and suturing or twisting of the vessels in case of larger ones. Medieval Arabic and to some extent also medieval medicine also relied on cauterization of exposed vessels, although these methods were used only when other methods were unavailable.

Now, when it comes to wound healing, the behaviour of the affected areas created of an important divide between the practitioners of medical art, although it has been resolved only in 19th century due to the development of microbiology. The differing opinions were caused by the approach to the process of suppuration, i.e. formation of pus in and around the wound. Some ancient scholars, most notably Hippocrates considered a pus to be a normal occurrence that should only be a point of concern it it had 'unfavourable' traits. In other words, a thick, light-coloured and relatively odourless discharge was considered a sign of proper healing, while watery and malodorous, especially when it was also containing blood, was a sign of problems. Although the concept of 'good pus' is often attributed to Galen, the latter generally followed a practice of drying and cleaning the wound as much as possible. The misunderstanding possibly stems from the Galen's writing on abscesses, where he says that they need to be evacuated and those filled with 'good' pus give better chance of healing. Today we know that the sebum-like thick pus with neutral odour is a result of the staphylococcus infection while the watery, malodorous one usually signifies more dangerous streptococcus infection. It is worth noting that the simple differentiation by smell largely stems from pretty naive association with filth and dirt, as e.g. suppuration caused by the infection with blue pus bacteria (Pseudomonas aeruginosa) has a slightly fruity smell, even though this particular microorganism is very resistant to most antiseptics and antibiotics, meaning that the infection is hard to get rid of. Nevertheless, the presence of pus was largely considered a secondary trait, with the healing being considered 'good' when none of the four main 'problematic' symptoms present, namely pain, the reddening of surrounding skin, tumescence (oedema) and increased surface temperature (expressed in Latin as dolor, rubor, tumor et calor). It is worth noting that Galen's assumption that pus is not necessarily a healthy symptom are mirrored in the collection of the Indian medical texts know as Suśruta Samhita dated to 7th century BCE, that divides the combat wound care into cleaning phase (vrana śodan) and healing phase (vrana ropan). It was stressed that the wound needs to be thoroughly cleaned of all foreign bodies and substances, otherwise a suppuration and pain might occur, what always is a sign of complications.

Hippocratic approach to pus was then challenged by Marcus Terentius Varro (116-27 BC) who suggested that every suppuration is a sign of contaminated wound and shows that the wound has not been properly cleaned. It is worth noting that Varro also also aware that the contaminants need not to be visible, as he also warned against settling near the marshlands, as the swamps 'breed certain minute creatures which cannot be seen by the eyes, but which float in the air and enter the body through the mouth and nose and cause serious diseases' (which is pretty much one of the earliest assumption of the existence of microorganisms, although the adverse influence of the marshlands was most likely caused by the mosquitoes transmitting malaria that in Varro's time was present in what is now Italy). This controversy was continued for centuries. The founder of the Bologna medical school, Ugo de Lucca and his student Theodoric (who allegedly both lived well into their nineties) proposed in the Chirurgia published in 1267 (finished by Theodoric ten years after the death of Hugh) that the suppuration (production of pus) is never a good sign and thus a surgeon needs to strive for clean, dry wound as any form of pus is a sign of problem. These ideas were also developed by Henri de Mondeville (1260-1320) who also considered any sort of suppuration to be caused by unfavourable condition caused by a 'contagion'. But Henri's successor, Guy de Chaulliac was partial to Hippocratic teachings and returned to the idea of 'laudable pus', although his works on wound treatment are pretty advanced and show that its author understood the importance of keeping wounds clean and properly maintained, having described detailed methods of reaproximation and apposition of the severed tissue as well as ways to facilitate healing. Nevertheless, these differences show that the approach to the wound healing by various medieval doctors could have differed in various places and times, largely depending on which works they were exposed to.