is chronic constipation dangerous

Yes, it is, and for the following reasons

Constipation predisposes you to all major colorectal disorders starting with enlarged hemorrhoids and ending up with colorectal cancer. The reasons aren‘t difficult to understand — your colon was designed by nature to hold a few pounds of feces in transit. When a person gets constipated, the colon may be holding 10, 20 or more lbs. The weight by itself isn‘t the problem, but the volume is – large, heavy stools enlarge and stretch out the colon, irritate the colon mucosa, harm the anal canal, and may produce toxins related to fermentation and rotting.

Constipation is one of the symptoms of dysbacteriosis — a condition where the normal, intestinal flora is dead and missing. When alive, this flora performs several, important functions. First, it protects the colon itself from any inflammation-causing pathogens. Second, it produces essential B-vitamins and vitamin K, responsible for blood clotting. Third, it governs primary immunity. And fourth — bacteria form stools, and keep them soft and moist. When all of these functions are compromised, you aren‘t likely to enjoy a long and healthy life!
Constipation significantly increases your risk of becoming a victim of medical error and/or of the side effects of drugs, all related to the treatment of any ensuing colorectal disorder.

Constipation affects genitourinary health, particularly for women, because the large intestine and the female reproductive organs reside in close proximity. These problems run the gamut from undue pressure on the uterus to rectal prolapse inside the vagina, from fecal incontinence to miscarriage from straining, and numerous other, equally nasty problems.
Constipation affects your quality of life, causes stress, and diminishes your overall sense of well-being. These things tend to self-perpetuate, and profoundly affect the cardiovascular, endocrine, and immune systems.
Closer to the end of one‘s life, chronic constipation strips the large intestine from its thinning, mucosal membrane, and causes flat lesions and polyps that eventually transform into colon cancer.