# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/ *[0-9]+([.,][0-9]+)?(\/[0-9]+([.,][0-9]+)?)? *//gm;t' <<< "400 mg
50/12,5 mg/ml
20 mikrog
500 mg/400 IU
60 mikrog/15 mikrog"
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html