About 100 Somalis gathered outside the British prime minister\'s residence, calling for a ban on khat, an herb they say causes serious problems, officials said. Khat, which is illegal in the United States and many countries in Europe, can cause euphoria, extreme talkativeness, dizziness, heart problems and anxiety when chewed, the BBC reported Thursday. Demonstrators said using khat can cause breakdowns within families and contributes to mental health problems. Research indicates more than a third of about 100,000 Somalis living in Britain have admitted to chewing khat on a daily basis. Abukar Awale, who said he is a former khat addict, organized the demonstration. \"I\'d like to bring to your attention a report, which came out in 2011, called \'khat related deaths\' there are 14 cases -- all young men, all of them died of liver failure,\" he told the BBC. \"They are not related. The one factor they all have in common is excessive khat use, which leads us to believe there is huge evidence of medical harm.\" A Home Office spokesman said the Advisory Council for the Misuse of Drugs is \"currently reviewing the harms associated with khat.\" \"The home secretary will consider the advice fully when it has been received, which is likely to be later this year,\" he said.