Witnesses have said incident occurred in miraa market in Mogadishu Abdulaziz district.
The three friends purchased the stimulant plant that is chewed by several Somalis but disagreed on the share before opening fire on each other.
Two died on the spot while other sustained injuries and nursing wounds.
Somalia is the big market for Kenyan grown stimulant plant that earns hundreds of millions of dollars in exchange for Kenyan farmers.
Somali police has earlier criminalized the use of drug the officers while on duty due to challenges of security mainly in the capital Mogadishu.
Famous Somali anti khat activist Abukar Awale is leading international campaign to ban the use of the khat also known as miraa in Somalia due to its social economic disadvantages.
EU countries like United Kingdom and Holland have already banned the use of the drug in their countries.
© Radio Dalsan