MK Tablet 50 is typically used to treat symptoms associated with allergies or asthma, and while most people tolerate it well, there may be some adverse effects. Headache, upset stomach, nausea, lightheadedness, and exhaustion are typical side effects. Additionally, some people may have mood swings, irritability, vivid dreams, or trouble sleeping. Anxiety, depression, or strange behavioural changes are uncommon but significant adverse effects that should be reported right away to a physician. It is generally regarded safe when used as recommended, but it should not be stopped or continued long-term without medical guidance, especially if symptoms alter or side effects arise.