Hi, Thanks for using the HCM. I am happy to address your questions, stop using ranitidine and get emergency medical help if you have any of these signs of an allergic reaction like hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop taking ranitidine and call your doctor at once if you have a serious side effect such as chest pain, fever, feeling short of breath, coughing up green or yellow mucus; unusual weakness; fast or slow heart rate; problems with your vision; fever, sore throat, and headache and red skin rash; or nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes). Less serious side effects may include headache (may be severe); drowsiness, dizziness; sleep problems (insomnia); decreased sex drive, impotence, or swollen or tender breasts (in men); nausea, vomiting, stomach pain; or diarrhea or constipation. This is not a complete list of side effects and others may occur. Call your doctor for medical advice if the side effects do not subside over few hours. Hope I have answered your query. If you have any further questions I will be happy to help. Thanks