When workers harvest tobacco without the necessary protective clothing, they are subjected to nicotine poisoning, and thus suffer from green tobacco sickness (GTS). It typically manifests as vomiting, headache, and dizziness. Further symptoms such as abdominal discomfort may occur . The onset of the illness is from a few hours to a few days after exposure to tobacco and may be self -limiting  . It is estimated that in one tobacco season, as many as a one in four workers experience GTS .
There are several factors that are associated with an increased risk of GTS. The first is the time that a worker has spent handling tobacco. Compared to experienced handlers, inexperienced handlers are more susceptible, as nicotine tolerance is built with prolonged exposure. Secondly, it has also been found that children are particularly predisposed to GTS for several reasons. Children often have no knowledge of the harmful effects of direct contact with tobacco leaves, and hence may not exercise caution. Furthermore, children have a higher body surface area to weight ratio, thus amplifying the effective dose delivered. It is further postulated that adult workers who smoke tobacco for years acquire a tolerance towards nicotine . Children are unlikely to have this advantage. Further investigations have shown that the younger the workers are, the greater their likelihood of developing GTS, and that both children and young adults are more easily affected by exogenous substances adversely  . In addition, water causes the delivery of nicotine to the skin to become more efficient. As a result, rain, sweat and other sources of moisture further intensify the risk .
An important aspect of GTS is that it induces a significant amount of vomiting that may lead to dehydration. Dehydration in turn, along with elevated body temperature, if severe enough, may contribute to the emergence of heat exhaustion and heat stroke. These illnesses require medical intervention, and heat stroke has potentially fatal repercussions. Along with pre-existing signs of GTS, symptoms indicative of a heat illness, such as seizures, confusion, diaphoresis and syncope may follow.
There are no set criteria for diagnosing green tobacco sickness, nor are there laboratory tests to aid the health worker. Moreover, the correct identification of GTS may be challenging due to its symptoms, that often mimic those of poisoning from synthetic substances used in pest control, as well as heat exhaustion and heat stroke. Inquiry about occupational history, specifically tobacco harvesting or handling, is thus imperative. It is also beneficial to ascertain the onset and duration of symptoms, as GTS has an acute presentation.