I don't think a week goes by where someone hasn't asked about how to eliminate a foul odour that's coming from a drain.
Usually this odour is concentrated in one part of the home. Once the area has been identified, you need to determine when it occurs. Is it only when the toilet is flushed? Is it only when you do the laundry? Maybe it occurs when it is raining outside. All of this information, along with any other details, are useful to help identify the cause.
Sometimes it is just a floor drain that has dried up. All floor drains are just big P-traps that are meant to hold water. The water is a seal to prevent odours and sewer gases from entering your home. If this water is not replenished on a regular basis, it will evaporate or it will leak out if the P-trap has failed, allowing a smell to enter your home.
Most times, all you need to do is pour a small bucket of water into the floor drain and the problem is solved!
Sometimes, the P-trap might have failed in some way, for instance it is cracked or broken and the water leaks out causing the smell to return. If this is the case, you will need to have a licensed plumber come to your home to assess the problem and recommend a permanent repair.