The 25-year-old failed a drug test at the world indoor championships in Portland, Oregon, where she won the bronze medal in the 4x400m relay, the Romanian athletic federation said in a statement.
"A document has arrived at the federation," its chair Sandu Ion told local media on Tuesday. "I've also talked to Mirela, I do not want to make further comments."
However, Sandu added that Lavric, who also won the world youth and junior titles in 800m, took the drug only at the end of last year.
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Meldonium, which helps boost blood flow and increases the amount of oxygen taken in by the body, was added to the World Anti-Doping Agency's list of banned substances on Jan. 1, 2016.
Since then, more than 100 athletes have been found to have used meldonium.
A study published last month showed the use of meldonium was widespread among elite atheletes competing at the European Games in Baku last year, with up to 490 people taking the drug during the competition.
Grindeks, the Latvian company that is the main supplier of the drug, says it could protect athletes from cell damage but was unlikely to improve their performance.
(Reporting by Angel Krasimirov; Editing by Gareth Jones)
