Being our first line of defense against many things trying to enter our bodies, the intestinal lining is well designed. However, it is rather fragile, as it is supposed to let digested nutrients through. It usually takes a number of different factors over a period of time to compromise the intestinal lining to the extent that we develop a leaky gut. Bacteria, fungi, yeast, such as candida, and other parasites can all damage the lining. Many drugs can as well, such as aspirin, ibuprofen, and other pain medications. Antibiotics, indirectly can cause it, by killing the beneficial bacteria in the gut, which allows harmful bacteria, and fungi to flourish. Anything that causes inflammation of the intestines can also damage the lining. This can be a difficult an lengthy process. I highly recommend seeing a health practitioner that specializes in it. In some countries there are several lab tests that can be done. These help not only in making an accurate diagnosis, but also in forming an efficient treatment plan.