Fact: For most people, the benefits of taking a blood thinner outweigh the downsides. Taking a blood thinner can prevent a stroke that might kill or disable you. There are potential downsides to taking a blood thinner: Taking a blood thinner can make you bleed or bruise more easily. You’ll need to take precautions and avoid activities that increase your risk of falling or having a head injury. Cost and inconvenience can be downsides. Depending on your own lifestyle and risk factors for stroke, these potential downsides may be more or less important for your decision.