Brief Answer:
Discoloured phlegm indicates infection.

Detailed Answer:
Hello Dear,

Though You have not specified the exact colour I presume it' yellowish. Does it contain blood?

Yellow or discoloured sputum generally indicate infection.

You are already being treated with antibiotics and I'm sure you will respond to them well.

I would like to suggest that sputum should be put up for test and antibiotic sensitivity so that appropriate antibiotic is used for better and quicker response.

Frequent nebulization will help to loosen the phlegm which will be easier to bring out by coughing. Similarly chest physiotherapy by an expert will help in clearing the chest of sputum.

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