Recent tabloid reports suggested that friends of the star were worried for her health, following her weight loss and the appearance of bruises close to veins on her arms.
It was also claimed that police and ambulance crews were called to her home at around 10.30pm on Tuesday, where they found Geldof with a man in his 30s who was "in respiratory arrest".
"I'm not on drugs," she told the Sunday Mirror. "The marks on my arms have been there since childhood. Check any picture - it's caused by a skin condition called psoriasis.
"As for the 30-year-old man OD-ing in my house, it's not true and my lawyers are dealing with this. It's about time people stopped thinking the worst of me. It's becoming very boring.
"If people feel the need to validate my weight loss by saying I'm on drugs then shame on them. I've changed my diet and the way I live. The truth is I just didn't want to treat my body badly anymore. I was never fat - it was just the fact that my diet was so unhealthy."
Geldof previously rubbished claims she was "flaunting" her recent weight loss.