Cannabis is the world's favourite drug, but also one of the least understood. Can cannabis cause schizophrenia? Is it addictive? Can it lead you on to harder drugs? Or is it simply a herb, an undervalued medicine? Addiction specialist Dr John Marsden discovers that modern science is finally beginning to find answers to these questions. John traces the cannabis plants' birthplace in Kazakhstan; finds the origins of our sensitivity to cannabis in the simple sea squirt; and finds out just what it does to our brains. He meets people who have been changed by this drug in drastically different ways - from those whose lives have been shattered to those who lives have been revived.

The drug policies have remained unchanged over the last 40 years so should they be reformed in the light of new research? Recent research has analysed the link between the harmful effects of drugs relative to their current classification by law with some startling conclusions. Perhaps most startling of all is that alcohol, solvents and tobacco (all unclassified drugs) are rated more dangerous than ecstasy, 4-MTA and LSD (all class A drugs).

We are in the grip of an allergy epidemic. 50 years ago one in 30 were affected, but in Britain today it is closer to one in three. Why this should be is one of modern medicine's greatest puzzles. In search of answers, Horizon travels round the globe, from the remotest inhabited island to the polluted centres of California and the UK. We meet sufferers and the scientists who have dedicated their lives trying to answer the mystery of why we are becoming allergic to our world.

What would happen if you ate nothing but fast food for an entire month? Filmmaker Morgan Spurlock does just that and embarks on the most perilous journey of his life. The rules? For 30 days he can't eat or drink anything that isn't on McDonald's menu; he must wolf three squares a day; he must consume everything on the menu at least once and supersize his meal if asked.
Spurlock also treks across the country interviewing a host of experts on fast food and an equal number of regular folk while chowing down at the Golden Arches. Spurlock's gruelling drive-through diet spirals him into a physical and emotional metamorphosis. Find out in 'Super Size Me' a look at the legal, financial and physical costs of America's hunger for fast food.

This series, presented by Robert Winston, takes us on a journey from birth to death using time-lapse photography, computer graphics and various state-of-the-art imaging techniques to explore every aspect, every nook and crevice of the human body in its various stages of growth, maturity and eventual decay. Though heart-warming in that it shows the commonality of human experience, The Human Body is also a potentially depressing reminder of our frail physicality and mortality." In this episode, follow Jeff and Phillippa from conception to the birth of their first child Bob in An Everyday Miracle. Learn why conception is the most dangerous part of your life, and the struggles that you must go through to even reach the first step. The couple openly discuss their concerns and joy throughout their entire pregnancy and this episode in particular would be well worth viewing by those who are expecting their first child. From experience, this tasteful and informative section captures aspects of pregnancy that the hospital-run Maternity Classes don't explain as well. You even get to see the birth of their child which makes for a great lead into the next section. And in case you were wondering, every day there are around 100 million acts of sexual intercourse taking place in the world resulting in around 910,000 conceptions.

Raging Teens follows a group of young boys and girls throughout their teenage years and captures the changes that the body undergoes through puberty. Its main focus, however, is on Beatrice and the changes she undergoes such as shopping, growing breasts, pubic hairs and her first period (her mother bought her some Chocolate Éclairs to help celebrate which must be a British thing). The boy's side covers testosterone and what changes it spurs in a lad's body such as facial hair, their voice cracking at the wrong time, and parts of the body that have until now lain dormant. You also learn that a pubic hair only grows for 6 months, which keeps it short, and is actually flat oval and not round which is why they curl.