Boil two cups of water and place in a bowl. Add about four or five drops of eucalyptus oil to the bowl for diffusion throughout the room. Start with a small number of drops and add more if needed as eucalyptus can cause irritation to the mucus membranes if too much of it is inhaled too quickly. While this method is not the most long-lasting, it will diffuse the scent throughout the room.
Place three drops each on pairs of cotton balls and place them in muslin bags. Tie the bags around different areas of your room, such as on bed posts, night stands and dressing tables.
Light a candle and let it burn for about five minutes. Blow the candle out, then place a drop of eucalyptus oil on the wax, though be careful not to place the oil on the wick, as essential oils are extremely flammable. Re-light the candle to diffuse the scent throughout the room.
Purchase a diffuser. There are several varieties available; simply choose the diffuser that best works for your needs. For example, lamp ring diffusers are inexpensive terra cotta rings that fit around a light bulb. The oil goes into the ring and the heat from the light bulb causes the scent to disperse. Fan diffusers are another option and blow the scent around the room from a tray or absorbent pad. Clay pot diffusers contain openings for placing drops of oil, with the oil permeating the pot and emitting the scent throughout the room.
Crush handfuls of eucalyptus leaves and place in muslin bags. Tie the bags around your room as desired.