The effects will vary based on dosage and the persons metabloism (tolerance, etc.). Codalgin Forte contains 30 mg of Codeine and 500 mg of acetaminophen (paracetamol). Codeine is used to relieve moderate to severe pain, if someone with no pain takes Codeine they will typically experience a "high" (euphoria). The problem with taking Codalgin Forte to achieve a "high" is that it takes much more than 30 mg of Codeine for the average person to achieve a good "high", so you will have to take several pills. Taking several pills poses a problem because each pill has 500 mg of acetaminophen, and the maximum recommended dose of acetaminophen is 1000 mg. So taking more than two pills at a time will exceed the recommended dose of acetaminophen. Exceeding the recommended dose of acetaminophen is very bad for your liver and over time will cause liver necrosis. So taking Codalgin Forte (one or two pills maximum) without a prescription is most likely not going to hurt you, unless you have an unknown alergic reaction or mix it with other drugs. Please note that I am not a physician and all my advise should be taken as such. You should not take pills that are not prescribed for you or in doses higher than recommended.