Always supplement fibre intake with fluids. Water, beverages and soups add fluid to the colon and bulk to stools, thus smoothening bowel movement. Small amounts of caffeine are useful, but excessive caffeine consumed through coffee, tea, colas and alcohol causes digestive irregularity. Vitamin C, calcium and vitamin B-complex and probiotics (live-friendly bacteria like lactobacillus) consumed through foods like yogurt and fermented milk are effective in treating constipation.
Amla, trifla, lemon and honey have been known for centuries to be antidotes to constipation.
Fats stimulate the flow of bile and lubricate the bowel. Intake of butter, ghee and virgin coconut oil in limited amounts as well as essential fatty acids (omega-3) like fish oil and ground flaxseeds is thus useful.

A diet consisting of whole grains, brown rice, millets, legumes, pulses, vegetables, fresh fruits, dry fruits, nuts and seeds with a daily intake of at least two litres of fluid can help prevent constipation.
Taking castor oil habitually has killed many, but cured none of constipation. Excessive intake of purgatives results in urinary tract infections, abdominal pain, low blood potassium and muscle weakness.
Passage of watery stools due to laxatives can cause loss of fluids and electrolyte imbalance (sodium and potassium), physical and mental weakness. In a susceptible person, it may even precipitate thrombosis in the heart or the brain.