The Harvest Green Mattress is naturally resistant to House Dust Mites. House Dust Mites can cause allergic rhinitis (hay fever), asthma, eczema and affect other associated diseases. Yes, dust mites can live in the organic cotton cover. But, they can not live in the deep layers within our mattress.  So, as far as hygiene is concerned, we recommend you cover your bed with an organic, micro-porous mattress protector.