Why is it that we like things that are bad for us? Take smoking for example; there is a devastating link between smoking and cancer but, despite hard-hitting health campaigns, the global consumption of cigarettes is rising. On page 733, Stephen Hecht attributes this to the deadly combination of nicotine addiction and the high carcinogen levels in tobacco. Smoking has produced strong evidence linking carcinogen exposure with cancer deaths and is a powerful model for understanding carcinogenesis.

Many parallels have been drawn between tobacco and cannabis. But, although smoking cannabis might be as harmful as smoking cigarettes, cannabis actually has wide-ranging benefits as a cancer treatment. The palliative effects of cannabis have been recognized for thousands of years and are caused by unique compounds called cannabinoids. Manuel Guzmán describes, on page 745, how cannabinoids exert palliative effects in patients with cancer. In addition, these compounds have a direct antitumour effect in preclinical studies and are being investigated in clinical trials.

When it comes to things that are good for us — like eating fruit and vegetables — there is definitely room for improvement. Young-Joon Surh provides encouragement on page 768 with an interesting discussion on dietary phytochemicals — another class of plant-derived chemicals reported to interfere with carcinogenesis. Dietary phytochemicals provide a cheap, accessible approach to chemoprevention and act by targeting intracellular-signalling cascades. Anticancer properties of numerous herbs and botanicals also feature in Web Watch.

Although we have a lot to learn about the pitfalls and benefits of consuming natural products, we are well on the way to discovering how more of them can be used to fight cancer.