Yes, Canesten cream can be safely used on a newborn baby with rashes resembling fungus. Apply it twice a day on the affected areas and a little around them, as fungal infections can spread quickly. It may take 5-7 days to see improvement and up to 14 days for the rash to fully clear. If the rashes improve, continue using the cream until they are fully healed plus an extra week. If the condition worsens, it is best to consult a pharmacist or pediatrician in person. It is important to keep the affected areas clean and dry as fungi thrive in moist environments.