<P> Tobacco package warning messages are warning messages that appear on the packaging of cigarettes and other tobacco products concerning their health effects . They have been implemented in an effort to enhance the public's awareness of the harmful effects of smoking . In general, warnings used in different countries try to emphasize the same messages . Warnings for some countries are listed below . Such warnings have been required in tobacco advertising for many years . </P> <P> The WHO Framework Convention on Tobacco Control, adopted in 2003, requires such package warning messages to promote awareness against smoking . </P> <P> A 2009 review summarises that "There is clear evidence that tobacco package health warnings increase consumers' knowledge about the health consequences of tobacco use ." The warning messages "contribute to changing consumers' attitudes towards tobacco use as well as changing consumers' behaviour ." </P>

When were health warnings put on cigarette packets