The Sick Rose is a very well known complex poem, and what is interesting about it, is that it can be interpreted in different levels or aspects;
On a superficial level, we can see that there's a rose which is being destroyed by a worm. But if we deeply analyse the poem, we'll understand what its "real" meaning is. We should first focus on the title; the word sick is more suitable for humans and diseased is usually used for a rose. The first line also mentions it and as a result we have an example of personification (furthermore it is written with capital letter). The "rose" (Any of numerous shrubs or vines of the genus Rosa, having prickly stems, compound leaves, and variously coloured, often fragrant flowers) symbolises love, innocence, beauty (representing women in a certain way) and its red colour gives the idea of passion.
The worm (Any of various crawling insect larvae, such as a grub or a caterpillar, having a soft elongated body) can be symbol of destruction, evil, harm, danger and illness (men; because they are attracted to beauty).
Its also important the fact that the worm is "invisible", "flies in the night", and has a "dark secret love"; a danger which cannot be stopped, desired and selfish (Caring supremely or unduly for one's self; regarding one's own comfort, advantage, etc., in disregard, or at the expense, of those of others), and attacks its prey destroying all the love and beauty it has. The "Darkness" (shade and obscurity) of the night and the worm's love make a contrast with the red colour and innocence of the rose ("crimson joy", crimson = red). All this are clear examples of how Blake "plays" with the connotation and denotation of the words, as well as the...