Houseplants may be more susceptible to some types of diseases and problems than outdoor plants because they are living, to some degree, in a foreign environment. Since your houseplants are living indoors instead of out, you may need to monitor them more closely to keep them healthy. By being aware of the signs, symptoms and treatments for houseplant health issues, you will be able to often cure house plants of diseases and problems.
Remove spotted, black or dead leaves using the sterile pruning technique. Sterile pruning requires you to wipe the blades of your clippers with rubbing alcohol in between each cut to prevent the spread of infection. Dispose of all plant debris in a sealed plastic bag.
Clean out your houseplant's pot. Plant material sitting underneath the plant can be a source of continuing infection. Remove all dead plant material from underneath the plant to remove a source of potential trouble.
Wipe down the plant with rubbing alcohol. Use a cotton swab saturated with the liquid. This will remove insect residues and remnants, such as webs from spider mites and "honey dew" from scale insects, killing invaders that it contacts without hurting your plant.
Spray the entire plant with a diluted mixture of dish detergent and water. Use a full bottle of water and 4 drops of dish detergent, swirled around. Do not shake it to make suds. Spray the upper and lower sides of the leaves as well as the stems. This will prevent insects from returning.
Monitor the plant's response to watering. If it appears wilted and does not respond to water, then it likely has root rot. You can replace the soil and attempt to remove damaged portions of the roots using sterile pruning techniques, but in most cases root rot will kill your houseplant.