The Putin critic returned to Russia after receiving treatment after being poisoned with what German scientists said was a Russian-made chemical weapon.

Cannabinoids, a class of prescription pills that contain synthetically-made chemicals found in marijuana, are associated with a 64 per cent increase in death among older adults with chronic obstructive pulmonary disease (COPD), according to the first published data on the impact of cannabinoids on the respiratory health of individuals with the lung disease.

Abnormal levels of more than two dozen metabolites -- chemicals produced in the body as it breaks down fats, proteins and carbohydrates -- can reliably predict which Sept. 11 firefighters developed lung disease and which did not, a new analysis shows.

E-cigarette vapor boosts the production of inflammatory chemicals and disables key protective cells in the lung that keep the air spaces clear of potentially harmful particles, reveals a small experimental study.

A resident of a San Francisco trailer park was arrested Friday after FBI agents found him in possession of chemicals that can be used to make explosives, according to police.

From a review of existing studies, researchers say that the active chemicals in cannabis - called cannabinoids - may help to treat various skin diseases.

A team of biophysicists set out to tackle the long-standing question about the nature of force generation by myosin, the molecular motor responsible for muscle contraction. The key question they addressed - one of the most controversial topics in the field - was: how does myosin convert chemical energy, in the form of ATP, into mechanical work? The answer revealed new details into how myosin, the engine of muscle and related motor proteins, transduces energy.

Using state-of-the-art fabrication and imaging, researchers watched the consequences of adding sculpted light to a catalyst during a chemical transformation. This work could inform more efficient -- and potentially new -- forms of catalysis.

Scientists have identified the presence of a non-tobacco plant in ancient Maya drug containers for the first time. The researchers detected Mexican marigold (Tagetes lucida) in residues taken from 14 miniature Maya ceramic vessels. The vessels also contain chemical traces present in two types of dried and cured tobacco.