One advantage of using frameworks derived from physics to predict cellular behavior is that they do not depend on the knowledge of underlying molecular details. Rather they rely on the systems’ statistical properties and symmetry arguments. Consequently, such unifying approaches provide an opportunity to reveal the potential simplicity of cellular behaviors that are intractable at the molecular level. An outstanding problem in modern medicine is to combat bacteria resistant to antibiotics and cancer cells resistant to chemotherapy treatments. Drug combinations are often used to counter resistance, but therapies developed on drug-sensitive cells often fail when applied to resistant mutants. Here, I will describe a series of experiments and theoretical approaches using scaling arguments, to infer the response of resistant cancer cells and bacteria to multidrug treatments. I will show that general symmetry arguments are sufficient to identify scaling laws in order to unify the behaviors of drug-resistant and drug-sensitive cells. Experiments validate these scaling laws, which hold for many cell types across all domains of life. Thus, such relationships may foster our understanding of drug resistance even before specific biochemical mechanisms have been elucidated.