A 19-year-old was taken to hospital after an alleged hammer attack early on Monday morning in Tranent.
Police said they were called to a property on King's Road, shortly before 6am after reports of a man suffering serious head injuries.
They said a 32-year-old man has been arrested and charged in connection with the incident and is expected to appear in Edinburgh Sheriff Court later this month.
A police spokesman said: "Police in East Lothian were called to the King's Road area of Tranent around 5.55am on Monday
following a man being found seriously injured.
"The 19-year-old was taken to the Edinburgh Royal Infirmary for treatment and a 32-year-old man has been arrested and charged in connection with this."
The condition of the teenager has not been released.
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