This was a case report of severe fatigue and bleeding in a 65-year-old man with ischemic heart disease who was wearing a stent and taking multiple medications for hypertension and diabetes. The use of a drug interaction and personalized prescription software (g-Nomic®) revealed potential interactions, involving acetylsalicylic acid and several non-pharmaceutical products including ginger, blueberry extracts, pineapple juice, docosahexaenoic acid and liquorice. Correction of these interactions resulted in complete remission of the reported side effects. This supports the idea that non-pharmaceuticals potentiated the effects of acetylsalicylic acid on haemostasis, producing the bleeding that would have caused fatigue. It is important to use appropriate tools to detect drug interactions that also take into account commonly used non-pharmaceutical products. Drug interactions can be considered illnesses by themselves.