Orchids and other plants are not suitable for indoor placement, as they can easily cause insomnia.

The fragrance of orchids can make people overly excited and cause insomnia. If the pollen released by the redbud flower (Cercis chinensis) comes into contact with a person for too long, it can trigger asthma or worsen coughing symptoms. The mimosine contained in the sensitive plant (Mimosa pudica) is a highly toxic organic compound, and excessive contact with the human body can cause hair loss. The rich fragrance released by the Chinese rose (Rosa chinensis) can cause some people to experience chest tightness, discomfort, a feeling of suffocation and difficulty breathing. The fragrance of lilies can also overstimulate the central nervous system and cause insomnia. When the night-blooming jessamine (Cestrum nocturnum) stops photosynthesis at night, it releases a large amount of waste gas, which can make patients with high blood pressure and heart disease feel depressed; at night it also releases a large number of particles that stimulate the sense of smell, and inhaling them for too long can make patients with high blood pressure and heart disease feel dizzy, depressed and uncomfortable, and may even worsen their condition. The aromatic scent of pine and cypress plants has an irritating effect on the human digestive system, not only affecting appetite but also making pregnant women feel restless, nauseated, vomiting, and dizzy. Geraniums can cause allergic reactions in some people; tulip flowers contain toxic alkaloids, and prolonged contact can make people feel dizzy and confused, and can also cause hair loss.

Toxic flowers also include Pinellia ternata, Monstera deliciosa, Euphorbia neriifolia, tiger thorn (Euphorbia milii), coral flower (Jatropha multifida), Excoecaria cochinchinensis, Lycoris radiata, yellow oleander (Thevetia peruviana), and others.