Step 1: General formula for product of roots.
For a polynomial of degree \(n\):
\[
a_n x^n + a_{n-1} x^{n-1} + \cdots + a_0 = 0,
\]
the product of roots = \((-1)^n \frac{a_0}{a_n}\).
Step 2: Identify coefficients.
Equation: \(x^4 + 1 = 0\).
Here, \(a_n = 1, \; a_0 = 1, \; n=4\).
Step 3: Substitution.
\[
\text{Product of roots} = (-1)^4 \cdot \frac{1}{1} = 1.
\]
Final Answer:
\[
\boxed{1}
\]