Complex sentence: Symptoms were not regarded as the body's attempt to fight the disease, but were considered a complication that would exacerbate the patient's condition and do further harm; a fever should be suppressed and any drugs used should be powerful and given in large dosages.
Split into simpler sentences: Symptoms were not regarded as the body's attempt to fight the disease, but were considered a complication that would exacerbate the patient's condition and do further harm. Practitioners believed that a fever should be suppressed and any drugs used should be powerful and given in large dosages.