Background:
More than 70 billion cigarettes are sold in Germany every year. An estimated 75% of butts are carelessly discarded in Germany, that would be around 53 billion butts that end up in the environment.

Objective:
To show the harm caused by discarded butts to the environment, animals and plants, as well as to show possible solutions to avoid the environmental harm of cigarette butts.

Methods:
A narrative review to give an overview on the latest evidence on environmental harms of cigarette butts.

Results:
Cigarette butts are the most frequent litter, concentrating in places where people gather. If butts get into the environment, the plastic filters degrade only very slowly; after two years, only around 15 to 20 percent of the butt has disappeared, depending on environmental conditions. The toxicants that are released from the butts pollute air, soil and water, thus harming water animals and accumulating in plants. The best solution to reduce environmental harm by littered cigarette butts, is to ban the use of filters in cigarettes and to reduce the number of smokers by effective tobacco prevention policies. A deposit return scheme as well as campaigns to raise awareness of smokers for the environmental problems caused by cigarette butts may be useful to reduce the amount of littered waste. Several ways of recycling the cellulose acetate of the filters are currently explored. In contrast, biodegradable filters made of cellulose are not a viable solution, as those filters take nearly as long as plastic filters to be degraded.

Conclusions:
Cigarette butts are a serious environmental hazard. The increasing environmental awareness of the population should be used to introduce measures that help to avoid cigarette butts being littered in the environment.